1. Field of the Invention
The present invention relates to a vehicle headlamp configured to change a light distribution pattern in accordance with a driving environment.
2. Related Art
A related art vehicle headlamp includes a light emitting device array having a plurality of semiconductor light emitting devices configured to irradiate a plurality of individual irradiation regions into which a region above the horizontal line is divided along the horizontal direction. With such vehicle headlamps, an adaptive driving beam (ADB) can be achieved by controlling the light emitting device array such that one or more individual irradiation regions corresponding to a position at which a forward vehicle or a pedestrian is detected is not irradiated, so as to avoid giving a glare to a driver of the forward vehicle or the pedestrian. In addition to dividing the region above the horizontal line along the horizontal direction, the light emitting device array may be configured such that the region is also divided along the vertical direction into plural stages so as irradiate individual irradiation regions arranged in a lattice structure, thereby being able to form a light distribution pattern having a vertical cutoff line (see, e.g., see JP2009-179121A).
However, when implementing the ADB by using of the individual irradiation regions arranged in a lattice structure, a width of the light distribution in the vertical direction is changed only by the height of the individual irradiation region. Therefore, a gap may be formed between the horizontal cutoff line of the light distribution pattern and the forward vehicle, in which case sufficient irradiation may not be provided in the vicinity of the horizontal cutoff line, which is important in view of ensuring distant visibility.